1. Field of the Invention
The present invention relates generally to lawnmowers and more particularly pertains to a lawnmower attachment which includes a pair of additional cutting blades driven by an independent power source mounted on the attachment and to facilitate reverse cutting operation without the fear of jackknifing during reverse motion of the lawnmower.
2. Description of the Prior Art
It is generally well known to utilize additional rotary cutting blades in operable connection with a single cutting blade associated with a lawnmower. For example, U.S. Pat. No. 3,483,684, issued to Price on Dec. 16, 1969, discloses a mounting linkage utilizable in combination with a tractor-type lawnmower, such linkage consisting of an attachment designed to replace an existing cutting blade with an assembly of three rotary cutting blades. This construction substantially increases the width of cut afforded by the tractor during an operation thereof, and it can be appreciated that the power supplied to the three blades comes from the same fuel-powered engine that drives the tractor. While this particular construction is effective in substantially increasing the width of a particular cut, it is apparent that it becomes a difficult operation to switch from the three cutting blade unit to a single cutting blade unit, and vice versa. In other words, no provision is made for easily and quickly dropping off two of the cutting blades while retaining the third in powered connection with the engine of the tractor. Additionally, the powering of three blades by the same engine which formerly only powered one such blade results in a substantial loss of driving and cutting power in the entire assembly.
As opposed to the approach of replacing the existing cutting blade on a tractor lawnmower, there have been several attempts to develop lawnmower attachments which are connectible to a tractor normally not having a cutting blade, through the use of a hitch mechanism. For example, U.S. Pat. No. 3,264,807, issued to Wallace on Aug. 9, 1966; U.S. Pat. No. 3,514,126, issued to Fuss on May 26, 1970; and U.S. Pat. No. 4,063,748, issued to Schmidt on Dec. 20, 1977, all disclose wheeled attachments which may be connected to a tractor or other pulling unit through the use of a hitch assembly, such pulling unit not having an individually powered cutting blade of its own. Further, in each of these patents, independent power supply means for rotating the cutting blades associated with the attachments are provided, so that no power is taken away from the pulling tractor during an operation of the mowers. While each of the inventions disclosed in these patents allows more versatility and ease of use than the afore-described Price lawnmower, none of these inventions are designed to facilitate a reverse cutting operation. In this regard, the hitch assemblies associated with each of the respective inventions permit a pivotal movement of the mower attachments relative to the tractors, so that any attempt in backing up such a tractor results in a jackknifing of the mower assembly attached thereto. Further, the particular means by which the respective cutting blades in the above-identified inventions are adjusted to a desired cutting depth are of a complex construction, usually involving multi-adjustments of the associated guide wheels to regulate such cutting depth.
In this connection, there has been at least one attempt to develop an efficient cutting blade depth adjustment means whereby minimal effort is required to adjust the blade cutting height. Specifically, U.S. Pat. No. 3,699,752, issued to Dandl on Oct. 24, 1972, discloses a modular constructed rotary mower which utilizes a drive shaft and gear box assembly to operate three mower cutting blades, while a hitch means is provided for connecting the same to a pulling unit such as a tractor. Through a simple rotation of the shaft to which the guide wheels are attached, the cutting blade height may be easily adjusted; however, this construction still suffers from the disadvantage of utilizing the tractor engine as the powering means for the three blades, while the provided hitch assembly permits the entire assembly to jackknife during a backing up of the pulling unit.
Accordingly, it can be appreciated that there still exists a need for a multi-blade mower attachment assembly which may be independently powered so as to not drain power from a pulling unit, which provides for easy blade cutting height adjustment, and which may be utilized without the fear of jackknifing during a backing up of the pulling unit. In this connection, the present invention substantially fulfills this need.